WO2024202136A1 - Epoxy resin composition, electronic component, semiconductor device, and semiconductor device manufacturing method - Google Patents

Abstract

To provide: an epoxy resin composition capable of suppressing small pores generated when the surface of a cured product thereof is polished; an electronic component using the epoxy resin composition; a semiconductor device using the epoxy resin composition; and a method for manufacturing the semiconductor device.　The epoxy resin composition contains an epoxy resin, a curing accelerator, a filler, and an elastomer. The elastomer is at least one selected from a solid elastomer and a liquid elastomer. The solid elastomer has a structure in which a double bond is not included in the main chain.

Description

Epoxy resin composition, electronic component, semiconductor device, and method for manufacturing semiconductor device

The present invention relates to an epoxy resin composition, an electronic component, a semiconductor device, and a method for manufacturing a semiconductor device.

Semiconductor devices in which semiconductor elements are mounted, such as personal computers and smartphones, are rapidly becoming smaller and more functional. Accordingly, improvements have been made to the methods of mounting semiconductor elements. One of these improvements is the improvement of the package manufacturing method.
Conventionally, packages were produced after semiconductor elements were separated into individual pieces, so the size of the package was always larger than the semiconductor element, and therefore the package obtained by the conventional package production method could not be mounted on a small semiconductor device.
Therefore, a technology for producing packages in the wafer state before the semiconductor elements are diced (hereinafter referred to as wafer level chip size packaging technology) has come to be used.

Wafer-level chip size packaging technology involves a process of encapsulating semiconductor elements with an encapsulant. One encapsulation method suitable for wafer-level chip size packaging technology is compression molding. Compression molding is a method in which a liquid encapsulant called liquid compression molding material is poured into the gap below the semiconductor element and the encapsulant is then hardened.

As such a liquid sealing material, for example, Patent Documents 1 and 2 propose a composition containing an epoxy resin, a hardener, and a filler.

International Publication No. 2018/221681 JP 2015-105304 A

In wafer-level chip-size packaging technology, after sealing with an encapsulant, a rewiring layer is formed on the portion of the hardened encapsulant that corresponds to the circuit surface of the semiconductor element. Before forming the rewiring layer, the surface of the hardened encapsulant is polished using a method such as chemical mechanical polishing (CMP) to flatten the surface of the hardened encapsulant.

However, when the cured surface of the encapsulant is polished using the CMP method, small holes may occur on the cured surface. Such small holes may affect the uniformity of the thickness of the redistribution layer. If the thickness of the redistribution layer is not uniform, the contact between the redistribution layer and the circuit surface or solder balls of the semiconductor element will be poor. As a result, when the semiconductor element is mounted on a semiconductor device, the electrical connection between the semiconductor element and other semiconductor elements will not be uniform, and this may cause defects in the semiconductor device.

The present invention aims to provide an epoxy resin composition that can suppress the formation of small holes when the surface of a cured product is polished, an electronic component that uses the epoxy resin composition, and a semiconductor device that uses the epoxy resin composition and a method for manufacturing the same.

In order to achieve the above object, one embodiment of the present invention is as follows.
(1) An epoxy resin composition comprising an epoxy resin, a curing accelerator, a filler, and an elastomer,
The elastomer is at least one selected from a solid elastomer and a liquid elastomer,
The solid elastomer is an epoxy resin composition having a structure having no double bond in the main chain.
(2) The epoxy resin composition according to (1) above, wherein after the surface of a cured product of the epoxy resin composition is polished by a first polishing step in which the surface is roughly polished and a second polishing step in which the surface is polished with a liquid containing an abrasive, the number of holes having a diameter of 0.05 μm to 0.5 μm present on the surface of the cured product is 10 or less per given area.
(3) The epoxy resin composition according to (1) or (2), wherein the content of the elastomer is 5.0 mass% or more based on the components excluding the filler from the epoxy resin composition.
(4) The epoxy resin composition according to any one of (1) to (3), wherein the solid elastomer is a core-shell type.
(5) The epoxy resin composition according to any one of (1) to (4), wherein the content of the elastomer is 5.0% by mass to 20.0% by mass, based on the components excluding the filler from the epoxy resin composition.
(6) The epoxy resin composition according to any one of (1) to (5), wherein the filler content is 73.0% by mass to 87.5% by mass.
(7) The epoxy resin composition according to any one of (1) to (6), wherein the viscosity at 120° C. is 0.5 Pa·s to 40.0 Pa·s.
(8) The epoxy resin composition according to any one of (1) to (7), wherein the curing accelerator is a heterocyclic compound containing a nitrogen atom.
(9) The epoxy resin composition according to any one of (1) to (8), further comprising at least one curing agent selected from the group consisting of a phenol-based curing agent, an amine-based curing agent, and an acid anhydride-based curing agent.
(10) The epoxy resin composition according to any one of (1) to (9), wherein the epoxy resin is at least one selected from the group consisting of an aliphatic epoxy resin and an aromatic epoxy resin.
(11) The epoxy resin composition according to any one of (1) to (10), which is used as a liquid compression molding material.
(12) An electronic part comprising a support and a cured product of the epoxy resin composition according to any one of (1) to (11).
(13) A semiconductor device having the electronic component according to (12).
(14) A method for producing a semiconductor device, comprising the steps of: filling a gap between a support and a semiconductor element disposed on the support with the epoxy resin composition according to any one of (1) to (11); curing the epoxy resin composition; and polishing the cured product of the epoxy resin composition.

The present invention provides an epoxy resin composition that can suppress the formation of small holes when the surface of a cured product is polished, an electronic component that uses the epoxy resin composition, and a semiconductor device that uses the epoxy resin composition and a method for manufacturing the same.

FIG. 1 is an SEM image of the surface of the cured epoxy resin material after the second polishing in Example 1. FIG. 2 is an SEM image of the surface of the cured epoxy resin material after the second polishing in Comparative Example 1.

(Epoxy resin composition)
The epoxy resin composition according to the embodiment contains an epoxy resin, a curing accelerator, a filler, and an elastomer, and preferably further contains a curing agent, and further contains other components as necessary.

<Epoxy resin>
The epoxy resin is not particularly limited as long as it is any of various epoxy resins generally used for semiconductor encapsulation and can be appropriately selected depending on the purpose, and examples thereof include aliphatic epoxy resins, aromatic epoxy resins, etc. These may be used alone or in combination of two types.

<<Aliphatic epoxy resin>>
The aliphatic epoxy resin is contained in order to impart flexibility to the cured product of the epoxy resin composition (hereinafter also simply referred to as "cured product"), and examples thereof include monofunctional aliphatic epoxy resins, difunctional aliphatic epoxy resins, polyfunctional aliphatic epoxy resins, etc. These may be used alone or in combination of two or more.

Monofunctional aliphatic epoxy resins are compounds that have one epoxy group in the molecule, and examples include alkyl alcohol glycidyl ethers such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; and alkenyl alcohol glycidyl ethers such as vinyl glycidyl ether and allyl glycidyl ether.

Difunctional aliphatic epoxy resins are compounds that have two epoxy groups in the molecule, such as alkylene glycol diglycidyl ether, poly(alkylene glycol) diglycidyl ether, and alkenylene glycol diglycidyl ether.

The polyfunctional aliphatic epoxy resin is a compound having three or more epoxy groups in the molecule, and examples thereof include polyglycidyl ethers of trifunctional or higher alcohols such as trimethylolpropane triglycidyl ether, pentaerythritol (tri- or tetra-)glycidyl ether, and dipentaerythritol (tri-, tetra-, penta- or hexa-)glycidyl ether, pentaerythritol, and dipentaerythritol.
The upper limit of the number of epoxy groups is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 5 or less.

Among these, multifunctional epoxy resins are preferred from the standpoint of reliability (thermal cycle resistance) and other factors.

The number average molecular weight of the aliphatic epoxy resin is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 200 to 2,000 from the viewpoint of imparting flexibility to the cured product of the epoxy resin composition.
The number average molecular weight of the aliphatic epoxy resin can be measured by a general method for measuring number average molecular weight.

The aliphatic epoxy resin may be a synthetic product or a commercially available product. Examples of commercially available products include Epogosey PT (general grade) (manufactured by Yokkaichi Synthetic Co., Ltd.), YX7400 (manufactured by Mitsubishi Chemical Corporation), SR-8EGS (manufactured by Sakamoto Pharmaceutical Co., Ltd.), and PG-207GS (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

<<Aromatic epoxy resin>>
Examples of aromatic epoxy resins include glycidyl ethers of phenols, glycidyl ether esters of hydroxycarboxylic acids, monoglycidyl esters or polyglycidyl esters of carboxylic acids, glycidylamine type epoxy resins, aminophenol type epoxy resins, epoxy resins having a naphthalene skeleton, novolac resins, etc. These may be used alone or in combination of two or more.

Examples of glycidyl ethers of phenols include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, catechol, and resorcinol. The glycidyl ethers of phenols may be synthesized or commercially available. Examples of commercially available products include YDF8170 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), YDF870GS (manufactured by Nippon Steel Chemical & Material Co., Ltd.), EXA-850CRP (manufactured by DIC Corporation), EXA-835LV (manufactured by DIC Corporation), and EP4005 (manufactured by ADEKA Corporation).

Examples of glycidyl ether esters of hydroxycarboxylic acids include p-hydroxybenzoic acid. The glycidyl ether esters of hydroxycarboxylic acids may be either synthesized or commercially available.

Examples of monoglycidyl esters or polyglycidyl esters of carboxylic acids include benzoic acid, phthalic acid, and terephthalic acid. The monoglycidyl esters or polyglycidyl esters of carboxylic acids may be either synthesized or commercially available.

Examples of glycidylamine type epoxy resins include diglycidyl aniline, diglycidyl toluidine, and tetraglycidyl-m-xylylenediamine. The glycidylamine type epoxy resin may be a synthetic product or a commercially available product. Examples of commercially available products include EP3980S (manufactured by ADEKA Corporation) and ZX1059 (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

Examples of aminophenol type epoxy resins include triglycidyl-p-aminophenol. The aminophenol type epoxy resins may be synthetic or commercially available. Examples of commercially available products include jER630 and jER630LSD (both manufactured by Mitsubishi Chemical Corporation) and EP3950L (manufactured by ADEKA Corporation).

Epoxy resins having a naphthalene skeleton include, for example, glycidyl esters of naphthol and glycidyl ether esters of β-hydroxynaphthoic acid. The epoxy resins having a naphthalene skeleton may be synthesized or commercially available products. Examples of commercially available products include HP4032, HP4032D, and HP4032SS (all manufactured by DIC Corporation).

Novolac resins include, for example, compounds obtained by converting phenols such as phenol, catechol, and resorcinol into novolacs. The novolac resin may be a synthetic product or a commercially available product. An example of a commercially available product is jER152 (manufactured by Mitsubishi Chemical Corporation).

Among these, it is preferable that the epoxy resin is a mixture of an aliphatic epoxy resin and an aromatic epoxy resin, in order to improve the curing properties while maintaining the hardness of the cured epoxy resin.

The ratio (mass ratio) of aliphatic epoxy resin to aromatic epoxy resin is not particularly limited and can be selected appropriately depending on the purpose, but aliphatic epoxy resin: aromatic epoxy resin = 20% to 40% by mass: 60% to 80% by mass is preferred.

<Curing accelerator>
The curing accelerator is contained in order to accelerate the crosslinking reaction between the epoxy resins and increase the curing rate of the epoxy resin. When the epoxy resin composition is cured, the curing accelerator is homopolymerized with the epoxy resin. That is, the curing accelerator does not remain in the crosslinked structure formed by the epoxy resin.
The curing accelerator is not particularly limited as long as it can cure the epoxy resin, and can be appropriately selected depending on the purpose. From the viewpoint of reliability (thermal cycle resistance), however, a heterocyclic compound containing a nitrogen atom is preferable.

<<Heterocyclic compounds containing nitrogen atoms>>
Examples of the heterocyclic compound containing a nitrogen atom include imidazole derivatives and microencapsulated heterocyclic compounds containing a nitrogen atom.

Examples of the imidazole derivative include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-imidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, benzimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, and 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole. These may be used alone or in combination of two or more.
The imidazole derivative may be a commercially available product or may be appropriately synthesized. Examples of commercially available products include 2P4MZ (2-phenyl-4-methylimidazole), 2MZA (2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 2-phenyl-4-methylimidazole) (both manufactured by Shikoku Chemical Industry Co., Ltd.).

The microencapsulated nitrogen-containing heterocyclic compound may be a commercially available product or may be appropriately synthesized. Commercially available products include, for example, Novacure HX3941HP, Novacure HXA3042HP, Novacure HXA3922HP, Novacure HXA3792, Novacure HX3748, Novacure HX3721, Novacure HX3722, Novacure HX3088, Novacure HX3741, Novacure HX3742, Novacure HX3613 (all manufactured by Asahi Kasei Corporation), Amicure PN-23J, Amicure PN-40J (all manufactured by Ajinomoto Fine-Techno Co., Ltd.), and Fujicure FXR-1121 (manufactured by Fuji Kasei Kogyo Co., Ltd.). These may be used alone or in combination of two or more types.

Among these, the nitrogen-containing heterocyclic compounds are preferably 2-phenyl-4-methylimidazole and 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine in terms of reactivity and storage stability.

The content of the nitrogen-containing heterocyclic compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 2.0% by mass to 8.0% by mass, and more preferably 2.5% by mass to 6.0% by mass, based on the epoxy resin composition excluding the filler described below. When the content of the nitrogen-containing heterocyclic compound is 2.0% by mass or more, the curing time of the epoxy resin composition can be shortened, and the productivity of electronic component devices is improved. When the content of the nitrogen-containing heterocyclic compound is 8.0% by mass or less, the storage stability of the epoxy resin composition is improved.
The content of the microencapsulated nitrogen-containing heterocyclic compound is preferably 3% by mass to 25% by mass, more preferably 5% by mass to 20% by mass, based on the epoxy resin composition excluding the filler as the active ingredient (heterocyclic compound containing nitrogen). When the content of the microencapsulated nitrogen-containing heterocyclic compound is 3% by mass or more, the curing time of the epoxy resin composition can be accelerated, and the productivity of the electronic component device can be improved. When the content of the microencapsulated nitrogen-containing heterocyclic compound is 25% by mass or less, the viscosity does not increase and the workability can be prevented from decreasing.

<Filler>
The filler is contained in the epoxy resin composition in order to adjust the properties of the cured product (mainly the linear expansion coefficient, elastic modulus, and water absorption).

The filler is not particularly limited and can be selected appropriately depending on the purpose. Examples of the filler include silica such as fused silica and crystalline silica; calcium carbonate, clay, alumina, silicon nitride, silicon carbide, boron nitride, calcium silicate, potassium titanate, aluminum nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, aluminum hydroxide, magnesium hydroxide, zinc borate, and zinc molybdate. These may be used alone or in combination of two or more. Among these, silica filler and alumina filler are preferred because they can increase the loading amount. The filler may be a synthetic product or a commercially available product. Examples of commercially available products include silica fillers such as SE101G-SMO (manufactured by Admatechs Co., Ltd.), SE605G-SMG (manufactured by Admatechs Co., Ltd.), and STW7010-20 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), and alumina fillers such as AG2051-SXM (manufactured by Admatechs Co., Ltd.).

The filler may be surface-treated. There are no particular limitations on the surface treatment agent, and it can be selected appropriately depending on the purpose. For example, a silane coupling agent can be used.

There are no particular limitations on the silane coupling agent, and it can be selected appropriately depending on the purpose. Examples include epoxy, methacrylic, amino, vinyl, glycidoxy, and mercapto types. Commercially available products include KBM403, KBE403, KBM503, and KBM573 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

The volume average particle size of the filler is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 μm to 15.0 μm, and more preferably 0.3 μm to 10.0 μm.
In the present embodiment, the volume average particle size refers to a particle size at which the volume cumulative particle size distribution measured by laser diffraction method is 50%.

The shape of the filler is not particularly limited and can be selected appropriately depending on the purpose. Examples include spherical, irregular, and flaky shapes.

The filler content is preferably 73.0% by mass to 87.5% by mass, and more preferably 75.0% by mass to 85.0% by mass, from the viewpoint of reducing the linear expansion coefficient of the cured product of the epoxy resin composition and workability. If the filler content is 73.0% by mass or less, the linear expansion coefficient of the cured product of the epoxy resin composition will be high, and warping may become significant. If the filler content is 87.5% by mass or more, the viscosity of the epoxy resin composition will be high, which may reduce workability.

<Elastomer>
The elastomer is contained in order to impart injectability to the epoxy resin composition and to improve the adhesive strength of the cured product of the epoxy resin composition.
The elastomer is at least one selected from a solid elastomer having a structure without a double bond in the main chain and a liquid elastomer, from the viewpoint of suppressing the generation of small holes when the surface of the cured product is polished. These may be used alone or in combination of two kinds.

When the surface of a cured product of a conventional epoxy resin composition containing an elastomer is polished, small holes may be generated. There are three main reasons for this. The first is the falling off of the elastomer portion present in the cured product of the epoxy resin composition. In general, cured products of elastomers have high abrasion resistance. For this reason, when the cured product of the epoxy resin composition is polished, the elastomer portion in the cured product of the epoxy resin composition is polished together with the epoxy resin and filler, etc., and falls off from the surface of the cured product of the epoxy resin composition. This fallen elastomer portion becomes a small hole. The second is the falling off of the filler present in the cured product of the epoxy resin composition. Depending on the polishing conditions, the filler falls off without being polished, similar to the elastomer portion described above. The third is damage to the polished surface of the cured product of the epoxy resin composition. Depending on the polishing conditions, the surface of the cured product of the epoxy resin composition is not polished, but a physical impact is applied, resulting in small holes.
Therefore, in the present embodiment, an elastomer having low abrasion resistance is used, which is believed to be able to suppress the generation of small holes when the surface of the cured product is polished.

<<Solid elastomer>>
A solid elastomer is an elastomer that is solid at room temperature (25°C) and has a structure that does not have a double bond in the main chain. An example of an elastomer that does not have a double bond in the main chain is silicone. Silicone has a siloxane bond and has low surface abrasion resistance due to polishing, etc., so that it can suppress small holes that occur when the surface of the cured product is polished and flattened.

From the viewpoint of compatibility with epoxy resins, the solid elastomer is preferably a core-shell type elastomer, which means that the outside of the core is covered with a material different from that of the core.
The core-shell type elastomer used in the embodiments is preferably an elastomer using a silicone resin for the core and an acrylic copolymer for the shell, since it exhibits a low elastic modulus within the temperature range in which the epoxy resin composition is used and can reduce the shrinkage stress of the epoxy resin composition.

When producing an epoxy resin composition using a core-shell type elastomer, the components of the epoxy resin composition may be mixed together at the same time, but it is preferable to disperse the elastomer in the epoxy resin before mixing, i.e., to carry out master batch processing and then mix it with other epoxy resin composition components to produce the epoxy resin composition.

<<Liquid elastomer>>
The liquid elastomer is also called a liquid elastomer, and is an elastomer that is liquid at room temperature (25° C.). The liquid elastomer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a copolymer of butadiene and acrylonitrile (butadiene-acrylonitrile copolymer).

The elastomer content is preferably 5.0% by mass or more, more preferably 5.0% by mass to 20.0% by mass, and even more preferably 8.0% by mass to 17.0% by mass, based on the components excluding the filler from the epoxy resin composition. If the elastomer content falls within this range, the adhesive strength can be improved and a decrease in workability due to high viscosity can be prevented.

<Curing Agent>
The curing agent is contained in order to cure the epoxy resin. When the epoxy resin composition is cured, the curing agent undergoes addition polymerization with the epoxy resin. That is, the curing agent enters into the crosslinked structure formed by the epoxy resin.
The curing agent is not particularly limited as long as it can cure the epoxy resin, and can be appropriately selected according to the purpose, and examples thereof include phenol-based curing agents, amine-based curing agents, and acid anhydride-based curing agents. These may be used alone or in combination of two or more.

The content of the curing agent is not particularly limited and can be appropriately selected depending on the purpose, but the stoichiometric equivalent ratio with the epoxy resin (curing agent equivalent/epoxy group equivalent) is preferably 0.01 to 1.00, more preferably 0.01 to 0.50, and even more preferably 0.08 to 0.30.
The content of the curing agent is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5% by mass to 2.0% by mass, and more preferably 0.5% by mass to 1.0% by mass.

<Other ingredients>
The other components are not particularly limited as long as they are those used in ordinary epoxy resin compositions and can be appropriately selected depending on the purpose, and examples thereof include colorants such as coupling agents, dyes, pigments, and carbon black; silicone oils; surfactants; antioxidants; conventionally known flame retardants such as antimony oxides such as antimony trioxide, antimony tetraoxide, and antimony pentoxide, and brominated epoxy resins; ion trapping agents; leveling agents; antifoaming agents; reactive diluents, etc. These may be used alone or in combination of two or more.

The content of other ingredients is not particularly limited and can be selected appropriately depending on the purpose.

<Physical Properties of Epoxy Resin Composition>
<<Viscosity>>
In the embodiment, the viscosity of the epoxy resin composition at 25° C. is preferably 1,000 Pa·s or less, more preferably 700 Pa·s or less, and even more preferably 500 Pa·s or less. From the viewpoint of handling, the viscosity of the epoxy resin composition at 25° C. is preferably 150 Pa·s or more.
In this specification, the viscosity is measured using an HB-DV type viscometer at a rotation speed of 10 rpm.

<<Hot Viscosity (at 120°C)>>
The viscosity of the epoxy resin composition in the embodiment at 120° C. is preferably 0.5 Pa·s to 40.0 Pa·s.
The viscosity at 120° C. can be measured by a rheometer.

<Physical Properties of Cured Epoxy Resin Composition>
In the cured product of the epoxy resin composition according to the embodiment, the number of small holes per given area after the surface of the cured product is polished by the first polishing and the second polishing is 10 or less.
The small holes referred to here are holes with a diameter of 0.05 μm to 0.5 μm among the holes on the surface of the cured material after polishing. The diameter refers to the maximum length of a line connecting two points on the periphery of the small hole, and the same applies when the hole is elliptical rather than circular.
The depth of the holes is set to 0.03 μm to 0.3 μm.

<<First Polishing>>
The first polishing is performed by roughly polishing (grinding) the surface of the cured product. Specifically, it is performed using waterproof abrasive paper. Examples of the abrasive grain size of the abrasive paper include #600, #800, and #1200. Examples of the polishing conditions when forming a polished surface by the first polishing include the following conditions.
The surface of the cured product is polished using a Struers automatic polishing machine (Tegramin-20, manufactured by Struers) under the following conditions.
Abrasive material: Water-resistant abrasive paper #600
Polishing time: 3 minutes. The rotation speed and polishing load were as follows.
Rotation speed: 150 rpm
Polishing load: 10N

<<Second Polishing>>
The second polishing is performed by a liquid containing an abrasive after the first polishing. The liquid containing an abrasive may be, for example, a liquid in which abrasive grains are dispersed in water. The liquid containing an abrasive may also be an abrasive slurry. Specifically, the second polishing is chemical mechanical polishing (CMP), that is, polishing by a polishing pad and a polishing slurry. The polishing conditions when forming a polished surface by the second polishing include, for example, the following conditions.
The surface of the cured product is polished using a Struers automatic polishing machine (Tegramin-20, manufactured by Struers) in the following order of steps 1 to 3 under the following conditions.
Step 1
Polishing material: Diamond slurry (Engis Japan Co., Ltd., 6-PC, 6μ slurry (particle size range: 4μm to 8μm))
Polishing time: 6 minutes Step 2
Polishing material: Diamond slurry (Engis Japan Co., Ltd., 1-PC, 1μ slurry (particle size range: 0μm to 2μm))
Polishing time: 3 minutes Step 3
Polishing member: Diamond slurry (Master prep, manufactured by BUEHLER, average particle size 0.05 μm)
Polishing time: 2 minutes. The rotation speed and polishing load in steps 1 to 3 are as follows.
Rotation speed: 150 rpm
Polishing load: 10N

The arithmetic mean roughness Ra of the polished surface of the cured product after the second polishing is preferably 500 nm or less, more preferably 300 nm or less, and even more preferably 100 nm or less. There is no particular lower limit for the arithmetic mean roughness Ra of the polished surface, and examples include 10 nm or more, 20 nm or more, etc.

The arithmetic surface roughness Ra of the polished surface can be calculated, for example, by measuring the surface of the cured epoxy resin composition after the second polishing using a confocal scanning electron microscope (OPTELICS H1200, manufactured by Lasertec Corporation) and using the method specified in JIS B 0601:2001.

The number of small holes on the surface of the cured epoxy resin composition polished by the first polishing and the second polishing can be measured by observing the surface with a scanning electron microscope (SEM) at a magnification of 5,000 times. The predetermined area in the above refers to one visual field in SEM observation, and is about 3.9 ^μm2 .
In SEM observation, the shading of the image obtained is determined according to the electron density, i.e., the shading in the SEM image is determined according to the type of compound.

<Method of producing epoxy resin composition>
The method for producing the epoxy resin composition according to the embodiment is not particularly limited and can be appropriately selected depending on the purpose. For example, the method includes mixing and stirring the above-mentioned components.
When the epoxy resin is in a solid state, it is preferable to liquefy and fluidize it by heating or the like before mixing.

The components may be mixed simultaneously, or some of the components may be mixed first and the remaining components may be mixed later. If it is difficult to uniformly disperse the filler in the epoxy resin, the epoxy resin and filler may be mixed first and the remaining components may be mixed later.

The equipment used for mixing and stirring is not particularly limited and can be selected appropriately depending on the purpose. Examples include roll mills, ball mills, planetary mixers, bead mills, Henschel mixers, and Raikai machines equipped with a stirrer and a heater.

<Uses of epoxy resin composition>
The epoxy resin composition according to the embodiment is an epoxy resin composition that can suppress the generation of small holes when the surface of a cured product is polished, and therefore can be suitably used as a liquid compression molding material.

(Electronic Components)
The electronic component according to this embodiment has a support and a cured product of the above-mentioned epoxy resin composition.
The electronic component may be, for example, one in which a semiconductor element and a support are sealed with an epoxy resin composition.

<Support>
The support is not particularly limited as long as it is capable of fixing a semiconductor element, and can be appropriately selected depending on the purpose. For example, a substrate and the like can be mentioned.

<<Substrate>>
The substrate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the substrate include a lead frame, a pre-wired tape carrier, a wiring board, glass, and a silicon wafer.
The size, shape and material of the substrate are not particularly limited as long as they are commonly used as substrates, and can be appropriately selected depending on the purpose.

<Semiconductor element>
The semiconductor element is not particularly limited and can be appropriately selected depending on the purpose. Examples of the semiconductor element include active elements such as semiconductor chips, transistors, diodes, and thyristors; and passive elements such as capacitors, resistors, resistor arrays, coils, and switches.
There are no particular limitations on the size, shape, and material of the semiconductor element, so long as they are used as ordinary semiconductor elements, and they can be appropriately selected depending on the purpose.

The cured epoxy resin composition is provided between the support and the semiconductor element.
The thickness of the cured product of the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose. For example, the thickness is from 10 μm to 800 μm.
The shape of the cured product of the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose.

(Semiconductor device)
The semiconductor device (semiconductor package) according to this embodiment includes the above-mentioned electronic components, and further includes other members as necessary.
The other members are not particularly limited and can be appropriately selected depending on the purpose.

(Method of manufacturing a semiconductor device)
The method for manufacturing a semiconductor device according to this embodiment includes a step of filling with an epoxy resin composition, a step of curing the epoxy resin composition, and a step of polishing the cured product of the epoxy resin composition, and may further include other steps as necessary.

<Step of filling epoxy resin composition>
The step of filling the epoxy resin composition is a step of filling the gap between the support and the semiconductor element disposed on the support with the epoxy resin composition. The method of filling the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a dispense method, a casting method, a printing method, and the like.
The amount of the epoxy resin composition to be filled is not particularly limited and can be appropriately selected depending on the purpose. For example, the amount is such that the thickness of the cured product of the epoxy resin composition is 10 μm or more and 800 μm or less.

<Step of curing the epoxy resin composition>
The step of curing the epoxy resin composition is a step of curing the epoxy resin composition between the support and the semiconductor element.
The method for curing the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose. Examples of the method include a method in which a support, an epoxy resin composition, and a semiconductor element are heated and cured while being compressed under reduced pressure (compression molding), a method in which a dispensed epoxy resin composition is heated and cured in a dryer, and a method in which a stencil-printed epoxy resin composition is heated and cured in a dryer.

<Step of polishing the cured epoxy resin composition>
The step of polishing the cured product of the epoxy resin composition is a step of polishing the surface of the obtained cured product of the epoxy resin composition to make the surface of the cured product flat.
The polishing method is not particularly limited and can be appropriately selected depending on the purpose. For example, the above-mentioned first polishing method and second polishing method can be mentioned.

<Other processes>
The other steps are not particularly limited and can be appropriately selected depending on the purpose. For example, there are a step of disposing a semiconductor element on a support, a step of forming a rewiring layer, and the like.

(Examples 1 to 13, Comparative Examples 1 to 4)
Epoxy resin compositions were prepared according to the formulations shown in Tables 1 to 4. The epoxy resin, curing accelerator, filler, elastomer, curing agent, and coupling agent were weighed, dispersed in a ceramic triple roll mill (manufactured by Inoue Seisakusho Co., Ltd.), and made into a paste to prepare the epoxy resin composition.
Unless otherwise specified, the values in the tables represent parts by mass.

The epoxy resins used in the examples and comparative examples are as follows.
Bisphenol F type epoxy resin (YDF8170, epoxy equivalent 158 g/eq., manufactured by Nippon Steel Chemical & Material Co., Ltd.)
Aminophenol type epoxy resin (jER 630, epoxy equivalent 98 g/eq., manufactured by Mitsubishi Chemical Corporation)
Aliphatic epoxy resin (Epogose PT (general grade), epoxy equivalent 435 g/eq., manufactured by Yokkaichi Synthetic Co., Ltd.)

The curing accelerators used in the examples and comparative examples are as follows.
2-Phenyl-4-methylimidazole (2P4MZ, manufactured by Shikoku Chemical Industries Co., Ltd.)
2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (2MZA, manufactured by Shikoku Chemical Industry Co., Ltd.)
Imidazole compound (2P4MHZ, manufactured by Shikoku Chemical Industries Co., Ltd.)

The fillers used in the examples and comparative examples are as follows.
Silica filler 1 (SE605G-SMG, surface treated with 3-methacryloxypropyltrimethoxysilane, average particle size 1.8 μm, top cut diameter 5 μm, manufactured by Admatechs Co., Ltd.)
Silica filler 2 (SE101G-SMO, surface treated with 3-methacryloxypropyltrimethoxysilane, average particle size 0.3 μm, top cut diameter 1 μm, manufactured by Admatechs Co., Ltd.)

The elastomers used in the examples and comparative examples are as follows.
Silicone rubber (core-shell type) (core-shell type silicone rubber particles, MX-965, manufactured by Kaneka Corporation, elastomer component 25%)
Silicone composite powder (KMP605, manufactured by Shin-Etsu Chemical Co., Ltd., 100% elastomer component)
- Butadiene-acrylonitrile copolymer (carboxyl-terminated butadiene-acrylonitrile copolymer, CTBN1008SP, manufactured by Chori GLEX Co., Ltd., elastomer component 100%)
Butadiene rubber (core-shell type) (core-shell type butadiene rubber particles, MX-137, manufactured by Kaneka Corporation, elastomer component 33%)
Polybutyl acrylate rubber (core-shell type) (core-shell type polybutyl acrylate rubber particles, ALBIDURE EP XP powder, manufactured by EVONIK, elastomer component 100%)
Silicone-acrylic composite rubber (Metablen S-2501, manufactured by Mitsubishi Chemical Corporation, 100% elastomer component)
Acrylic rubber (core-shell type) (core-shell type acrylic rubber particles, Staphyloid AC3355, manufactured by Aica Kogyo Co., Ltd., elastomer component 100%)

The curing agents used in the examples and comparative examples are as follows.
Phenol-based hardener (MEH-8005, hydroxyl equivalent 139 g/eq. to 143 g/eq., manufactured by Meiwa Kasei Co., Ltd.)
Amine-based hardener (ETHACURE 100 PLUS, manufactured by Albemarle)
・Acid anhydride curing agent (HN-2200, manufactured by Showa Denko Materials Co., Ltd.)

Other components used in the examples and comparative examples are as follows.
Coupling agent (3-isocyanatepropyltriethoxysilane, KBE-9007, manufactured by Shin-Etsu Chemical Co., Ltd.)

The obtained epoxy resin composition was measured and evaluated for viscosity, hot viscosity, adhesive strength, number of holes on the surface after polishing, and surface roughness. The measurement and evaluation results are shown in Tables 1 to 4.

<Viscosity, hot viscosity>
Using an HB-DV type viscometer (HB-DV1, manufactured by Brookfield Instruments), the viscosity of each epoxy resin composition immediately after preparation was measured at a liquid temperature of 25° C. and at 10 rpm or 5 rpm, and evaluated based on the following evaluation criteria.
-Evaluation criteria-
A: Viscosity is 1,000 Pa·s or less B: Viscosity is more than 1,000 Pa·s Furthermore, the hot viscosity at 120°C was measured using a rheometer (MARSIII, manufactured by HAAKE Corporation). Each epoxy resin composition (0.3 mL±0.1 mL) was placed on a plate heated to 120°C, and measurement was started with a measurement frequency of 10 Hz, a strain amount of 0.5, a gap of 0.5 mm, and a measurement frequency of 1 second. The hot viscosity after 40 seconds was measured, and this was taken as the measurement result of the hot viscosity at 120°C.

<Adhesive strength>
Each epoxy resin composition was attached to a 10 mm square silicon chip using a mold so as to form a truncated cone shape with a bottom diameter of 5 mm, a top diameter of 3 mm, and a height of 6 mm, and then cured for 2 hours at 150° C. to prepare a test specimen. The resin portion of the test specimen was peeled off with a bond tester (Dage 4000, manufactured by Nordson Advanced Technologies) to measure the shear bond strength.
The adhesive strength was evaluated based on the shear adhesive strength value and the following evaluation criteria.
-Evaluation criteria-
A: Shear adhesive strength is 8 MPa or more. B: Shear adhesive strength is 6 MPa or more and less than 8 MPa. C: Shear adhesive strength is less than 6 MPa.

<Number of holes on the surface after polishing>
Each epoxy resin composition was compression molded onto a 12-inch silicon wafer to a thickness of 300 μm. The wafer was then cut into approximately 50 individual pieces, and the surface of the cured epoxy resin composition on each individual silicon wafer was polished by the first polishing method and then by the second polishing method.

The first polishing method was polishing with a waterproof abrasive paper (#600) using a polishing machine (Tegramin-20, manufactured by Struers). The polishing time was 3 minutes, the rotation speed was 150 rpm, and the polishing load was 10 N.
The second polishing method was carried out using a polishing machine (Tegramin-20, manufactured by Struers) in the order of steps 1 to 3 shown below.
Step 1
Polishing material: Diamond slurry (Engis Japan Co., Ltd., 6-PC, 6μ slurry (particle size range: 4μm to 8μm))
Polishing time: 6 minutes Step 2
Polishing material: Diamond slurry (Engis Japan Co., Ltd., 1-PC, 1μ slurry (particle size range: 0μm to 2μm))
Polishing time: 3 minutes Step 3
Polishing member: Diamond slurry (Master prep, manufactured by BUEHLER, average particle size 0.05 μm)
Polishing time: 2 minutes The rotation speed and polishing load in steps 1 to 3 were as follows.
Rotation speed: 150 rpm
Polishing load: 10N

The polished surface of the cured epoxy resin composition was observed with a SEM (MERLIN, manufactured by ZEISS) at a magnification of 50,000 times, the number of holes with diameters of 0.05 μm to 0.50 μm present in one field of view was counted, and the surface condition after polishing was evaluated based on the following evaluation criteria. The SEM image of Example 1 is shown in FIG. 1, and the SEM image of Comparative Example 1 is shown in FIG. 2.
The area of one field of view in 50,000x SEM observation is approximately 3.9 ^μm2 .
-Evaluation criteria-
A: The number of holes of 0.05 μm to 0.50 μm on the polished surface is 9 or less. B: The number of holes of 0.05 μm to 0.50 μm on the polished surface is 10 or more.

<Measurement of surface roughness (Ra)>
The surface of the cured epoxy resin composition after the second polishing was measured using a confocal scanning electron microscope (OPTELICS H1200, manufactured by Lasertec Corporation), and Ra was calculated according to the method specified in JIS B 0601:2001.
The measurement conditions were as follows: scan width was 100 μm, scan type was area, light source was Blue, cutoff value was 1/5, object lens was x100, contact lens was x14, digital zoom was x1, and Z pitch was 10 nm. The Ra value was measured at three locations and the average value was calculated.

As shown in Tables 1 to 4, the epoxy resin compositions of the Examples were all rated as "A" for the number of pores on the polished surface. These epoxy resin compositions were epoxy resin compositions that could suppress the generation of small pores when the surface of a cured product was polished.
On the other hand, in Comparative Examples 1 to 4, in which a solid elastomer having a double bond in the main chain was used as the elastomer, the number of pores on the surface after polishing was all rated as "B." From these results, it became clear that an epoxy resin composition containing a solid elastomer or liquid elastomer having no double bond in the main chain as the elastomer can suppress the generation of small pores when the surface of the cured product is polished.

Although the embodiments and examples of the present invention have been described, these are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and gist of the invention.

Claims (14)

An epoxy resin composition comprising an epoxy resin, a curing accelerator, a filler, and an elastomer,
The elastomer is at least one selected from a solid elastomer and a liquid elastomer,
Epoxy resin composition, characterized in that the solid elastomer has a structure having no double bond in the main chain. The epoxy resin composition according to claim 1, in which the number of holes having a diameter of 0.05 μm to 0.5 μm present on the surface of the cured product is 10 or less per given area after the surface of the cured product is polished by a first polishing step in which the surface is roughly polished and a second polishing step in which the surface is polished by a liquid containing an abrasive. The epoxy resin composition according to claim 1 or 2, wherein the content of the elastomer is 5.0 mass% or more based on the components of the epoxy resin composition excluding the filler. The epoxy resin composition according to any one of claims 1 to 3, wherein the solid elastomer is a core-shell type. The epoxy resin composition according to any one of claims 1 to 4, wherein the content of the elastomer is 5.0% by mass to 20.0% by mass based on the components of the epoxy resin composition excluding the filler. The epoxy resin composition according to any one of claims 1 to 5, wherein the filler content is 73.0% by mass to 87.5% by mass. The epoxy resin composition according to any one of claims 1 to 6, having a viscosity at 120°C of 0.5 Pa·s to 40.0 Pa·s. The epoxy resin composition according to any one of claims 1 to 7, wherein the curing accelerator is a heterocyclic compound containing a nitrogen atom. The epoxy resin composition according to any one of claims 1 to 8, which contains at least one curing agent selected from a phenol-based curing agent, an amine-based curing agent, and an acid anhydride-based curing agent. The epoxy resin composition according to any one of claims 1 to 9, wherein the epoxy resin is at least one selected from an aliphatic epoxy resin and an aromatic epoxy resin. The epoxy resin composition according to any one of claims 1 to 10, which is used as a liquid compression molding material. A support;
An electronic part comprising a cured product of the epoxy resin composition according to any one of claims 1 to 11. A semiconductor device having the electronic component according to claim 12. A method for manufacturing a semiconductor device, comprising the steps of filling a gap between a support and a semiconductor element disposed on the support with the epoxy resin composition according to any one of claims 1 to 11, curing the epoxy resin composition, and polishing the cured product of the epoxy resin composition.